In compliance with numerous and varied user requirements, mobile communication terminals, each equipped with a game function, are provided. Such a mobile communication terminal equipped with a game function is implemented as a one-person game which allows a user to enjoy the game with an artificial intelligence character. Such a game is problematic in that the user easily gets bored with programmed rules that the artificial intelligent character uses when coping with the user.
In order to solve this problem, a network game, in which a plurality of mobile communication terminals is connected to each other through a mobile communication network and a plurality of users plays a game in a singular game environment, has been proposed. Since a network game is executed in such a way that a plurality of users interacts with each other, games are not repetitive, and thus users interests are stimulated. However, such a network game is problematic in that, since respective mobile communication terminals are used while making connections to a mobile communication network, communication fees may be a burden, and thus it is difficult to activate a network game.